<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN">
<html>
 <head>
  <title>The Second Acid Test</title>
  <style type="text/css">
   /* section numbers refer to CSS2.1 */

   /* page setup */
   html { font: 12px sans-serif; margin: 0; padding: 0; overflow: hidden; /* hides scrollbars on viewport, see 11.1.1:3 */ background: white; color: red; }
   body { margin: 0; padding: 0; }

   /* introduction message */
   .intro { font: 2em sans-serif; margin: 3.5em 2em; padding: 0.5em; border: solid thin; background: white; color: black; position: relative; z-index: -2; /* should cover the black and red bars that are fixed-positioned */ }
   .intro * { font: inherit; margin: 0; padding: 0; }
   .intro h1 { font-size: 1em; font-weight: bolder; margin: 0; padding: 0; }
   .intro :link { color: blue; }
   .intro :visited { color: purple; }

   /* picture setup */
   #top { margin: 0 3em 0; padding: 2em 0 0 .5em; text-align: left; font: 2em/24px sans-serif; color: navy; white-space: pre; } /* "Hello World!" text */
   .picture { position: relative; border: 1em solid transparent; margin: 0 0 0 3em; } /* containing block for face */
   .picture { background: red; } /* overriden by preferred stylesheet below */

   /* top line of face (scalp): fixed positioning and min/max height/width */
   .picture p { position: fixed; margin: 0; padding: 0; border: 0; top: 9em; left: 11em; width: 140%; max-width: 4em; height: 8px; min-height: 1em; max-height: 2mm; /* min-height overrides max-height, see 10.7 */ background: black; border-bottom: 0.5em yellow solid; }

   /* bits that shouldn't be part of the top line (and shouldn't be visible at all): HTML parsing, "+" combinator, stacking order */
   .picture p.bad { border-bottom: red solid; /* shouldn't matter, because the "p + table + p" rule below should match it too, thus hiding it */ }
   .picture p + p { background: maroon; z-index: 1; } /* shouldn't match anything */
   .picture p + table + p { margin-top: 3em; /* should end up under the absolutely positioned table below, and thus not be visible */ }

   /* second line of face: attribute selectors, float positioning */
   [class~=one].first.one { position: absolute; top: 0; margin: 36px 0 0 60px; padding: 0; border: black 2em; border-style: none solid; /* shrink wraps around float */ }
   [class~=one][class~=first] [class=second\ two][class="second two"] { float: right; width: 48px; height: 12px; background: yellow; margin: 0; padding: 0; } /* only content of abs pos block */

   /* third line of face: width and overflow */
   .forehead { margin: 4em; width: 8em; border-left: solid black 1em; border-right: solid black 1em; background: red url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAIAAACQd1PeAAAADElEQVR42mP4%2F58BAAT%2FAf9jgNErAAAAAElFTkSuQmCC); /* that's a 1x1 yellow pixel PNG */ }
   .forehead * { width: 12em; line-height: 1em; }

   /* class selectors headache */
   .two.error.two { background: maroon; } /* shouldn't match */
   .forehead.error.forehead { background: red; } /* shouldn't match */
   [class=second two] { background: red; } /* this should be ignored (invalid selector -- grammar says it only accepts IDENTs or STRINGs) */

   /* fourth and fifth lines of face, with eyes: paint order test (see appendix E) and fixed backgrounds */
   /* the two images are identical: 2-by-2 squares with the top left
      and bottom right pixels set to yellow and the other two set to
      transparent. Since they are offset by one pixel from each other,
      the second one paints exactly over the transparent parts of the
      first one, thus creating a solid yellow block. */
   .eyes { position: absolute; top: 5em; left: 3em; margin: 0; padding: 0; background: red; }
   #eyes-a { height: 0; line-height: 2em; text-align: right; } /* contents should paint top-most because they're inline */
   #eyes-a object { display: inline; vertical-align: bottom; }
   #eyes-a object[type] { width: 7.5em; height: 2.5em; } /* should have no effect since that object should fallback to being inline (height/width don't apply to inlines) */
   #eyes-a object object object { border-right: solid 1em black; padding: 0 12px 0 11px; background: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAABnRSTlMAAAAAAABupgeRAAAABmJLR0QA%2FwD%2FAP%2BgvaeTAAAAEUlEQVR42mP4%2F58BCv7%2FZwAAHfAD%2FabwPj4AAAAASUVORK5CYII%3D) fixed 1px 0; }
   #eyes-b { float: left; width: 10em; height: 2em; background: fixed url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAIAAAD91JpzAAAABnRSTlMAAAAAAABupgeRAAAABmJLR0QA%2FwD%2FAP%2BgvaeTAAAAEUlEQVR42mP4%2F58BCv7%2FZwAAHfAD%2FabwPj4AAAAASUVORK5CYII%3D); border-left: solid 1em black; border-right: solid 1em red; } /* should paint in the middle layer because it is a float */
   #eyes-c { display: block; background: red; border-left: 2em solid yellow; width: 10em; height: 2em; } /* should paint bottom most because it is a block */

   /* lines six to nine, with nose: auto margins */
   .nose { float: left; margin: -2em 2em -1em; border: solid 1em black; border-top: 0; min-height: 80%; height: 60%; max-height: 3em; /* percentages become auto (see 10.5 and 10.7) and intrinsic height is more than 3em, so 3em wins */ padding: 0; width: 12em; }
   .nose > div { padding: 1em 1em 3em; height: 0; background: yellow; }
   .nose div div { width: 2em; height: 2em; background: red; margin: auto; }
   .nose :hover div { border-color: blue; }
   .nose div:hover :before { border-bottom-color: inherit; }
   .nose div:hover :after { border-top-color: inherit; }
   .nose div div:before { display: block; border-style: none solid solid; border-color: red yellow black yellow; border-width: 1em; content: ''; height: 0; }
   .nose div    :after { display: block; border-style: solid solid none; border-color: black yellow red yellow; border-width: 1em; content: ''; height: 0; }

   /* between lines nine and ten: margin collapsing with 'float' and 'clear' */
   .empty { margin: 6.25em; height: 10%; /* computes to auto which makes it empty per 8.3.1:7 (own margins) */ }
   .empty div { margin: 0 2em -6em 4em; }
   .smile { margin: 5em 3em; clear: both; /* clearance is negative (see 8.3.1 and 9.5.1) */ }

   /* line ten and eleven: containing block for abs pos */
   .smile div { margin-top: 0.25em; background: black; width: 12em; height: 2em; position: relative; bottom: -1em; }
   .smile div div { position: absolute; top: 0; right: 1em; width: auto; height: 0; margin: 0; border: yellow solid 1em; }

   /* smile (over lines ten and eleven): backgrounds behind borders, inheritance of 'float', nested floats, negative heights */
   .smile div div span { display: inline; margin: -1em 0 0 0; border: solid 1em transparent; border-style: none solid; float: right; background: black; height: 1em; }
   .smile div div span em { float: inherit; border-top: solid yellow 1em; border-bottom: solid black 1em; } /* zero-height block; width comes from (zero-height) child. */
   .smile div div span em strong { width: 6em; display: block; margin-bottom: -1em; /* should have no effect, since parent has top&bottom borders, so this margin doesn't collapse */ }

   /* line twelve: line-height */
   .chin { margin: -4em 4em 0; width: 8em; line-height: 1em; border-left: solid 1em black; border-right: solid 1em black; background: yellow url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAIAAAFSDNYfAAAAaklEQVR42u3XQQrAIAwAQeP%2F%2F6wf8CJBJTK9lnQ7FpHGaOurt1I34nfH9pMMZAZ8BwMGEvvh%2BBsJCAgICLwIOA8EBAQEBAQEBAQEBK79H5RfIQAAAAAAAAAAAAAAAAAAAAAAAAAAAID%2FABMSqAfj%2FsLmvAAAAABJRU5ErkJggg%3D%3D) /* 64x64 red square */ no-repeat fixed /* shouldn't be visible unless the smiley is moved to the top left of the viewport */; }
   .chin div { display: inline; font: 2px/4px serif; }

   /* line thirteen: cascade and selector tests */
   .parser-container div { color: maroon; border: solid; color: orange; } /* setup */
   div.parser-container * { border-color: black; /* overrides (implied) border-color on previous line */ } /* setup */
   * div.parser { border-width: 0 2em; /* overrides (implied) declarations on earlier line */ } /* setup */

   /* line thirteen continued: parser tests */
   .parser { /* comment parsing test -- comment ends before the end of this line, the backslash should have no effect: \*/ }
   .parser { margin: 0 5em 1em; padding: 0 1em; width: 2em; height: 1em; error: \}; background: yellow; } /* setup with parsing test */
   * html .parser {  background: gray; }
   \.parser { padding: 2em; }
   .parser { m\argin: 2em; };
   .parser { height: 3em; }
   .parser { width: 200; }
   .parser { border: 5em solid red ! error; }
   .parser { background: red pink; }

   /* line fourteen (last line of face): table */
   ul { display: table; padding: 0; margin: -1em 7em 0; background: red; }
   ul li { padding: 0; margin: 0; }
   ul li.first-part { display: table-cell; height: 1em; width: 1em; background: black; }
   ul li.second-part { display: table; height: 1em; width: 1em; background: black; } /* anonymous table cell wraps around this */
   ul li.third-part { display: table-cell; height: 0.5em; /* gets stretched to fit row */ width: 1em; background: black; }
   ul li.fourth-part { list-style: none; height: 1em; width: 1em; background: black; } /* anonymous table cell wraps around this */

   /* bits that shouldn't appear: inline alignment in cells */
   .image-height-test { height: 10px; overflow: hidden; font: 20em serif; } /* only the area between the top of the line box and the top of the image should be visible */
   table { margin: 0; border-spacing: 0; }
   td { padding: 0; }

  </style>
  <link rel="appendix stylesheet" href="data:text/css,.picture%20%7B%20background%3A%20none%3B%20%7D"> <!-- this stylesheet should be applied by default -->
 </head>
 <body>
  <h2 id="top">Hello World!</h2>

  <div class="picture">
   <p><table><tr><td></table><p class="bad"> <!-- <table> closes <p> per the HTML4 DTD -->
   <blockquote class="first one"><address class="second two"></address></blockquote>
   <div class="forehead"><div>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</div></div>
   <div class="eyes"><div id="eyes-a"><object data="data:application/x-unknown,ERROR"><object data="/404-dir-should-not-exist/" type="text/html"><object data="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAGAAAAAYCAYAAAFy7sgCAAAGsUlEQVRo3u2ZbWwcZxHHf3s%2B7LNbO3ZjXBtowprGODRX0qpNQCjmJKuVKhMl1P2AkCwhFOIKkCBSm9IXavGFKAixIAECwkmWo5MrhRI3Ub40IEwQgp6aIDg3Cd6eEqyIHEteah%2B1E69vhw%2BZtTaX8704ZzkKjHS6271nZ56ZZ%2BY%2F%2F%2BdZKF%2FCwYshx3EkkggLsD1v4FQkEZZYLCbAKyG9%2Ba9EIsG6hnUAf8x74K3aUC3j4%2BM54HcsR2oAIomwZOezkv%2FnSHpYNh%2BNCmAE7xv94zvFdd1bHsjMZmQkPSxAJP%2B%2FfuBLwK54PC7JZFKAVJmzXLBt2w%2FMvcDLwIb8QS8CeJ4nkURYIomw7J%2FYJ8BvSiiXptGGxWds2%2Fa9%2Bnaxh%2BYAD%2Bgt04NDgABTpQY2cvvSFLzw86gWeBVwC8SzlOSv2YeBPfmDBoBHgKmR9LBEEmHZfDTqGykqfkUE0nA78BzQGfSgUeP3wNeTXwXg7MwZDhw4UHL6ra2ti79%2FOvljgG8AZ4H64Lhm4MvAocxsRppGG%2FxcXihlwLIs6R%2FfKV2HO%2F26uA94pdDYUKUZUU7W1RQYXA98Gnhaf5%2FXWX0HeAHYoQonqa4sZSOsSWMCWeC9Yko%2BCQwBe4E6oNc0Tc91XTl1%2BaTsn9gnI%2Blhyc5nZWxsrBIkKSbl2tiic3tW53YDEwOKaoFBrcOfqKee53lG9xsPMjV784r%2F4lO%2FpPvyJ9iyZcuvFSaXK5XYeAZ4CDgGvB3MS4B54LQuWYPeuy4iRFsevsXqpuYoqVQKIH2bK1CuDQNo11o4XUzh%2FcDWYIe1LEtyuZx4niee54njOGKapgfsqlL%2Bl2OjEXg8nxrc1dJ0h3hbtL%2BGCtz7KPBF4CuBe9uB15VafE8hr9qylI3HgG8C2%2FK7VyHZoJj7MrBRm30qFotJMpkU27YlHo%2F7Ha5a%2BV%2FKRkSJ4KuKRLVLKapTjB1SzAVIjY2NSXY%2BKyPpYdk%2FsU9OXT4pruv6BdZbBQfKsVGnvWlIe1VB6VQO8JxC1vZYLCbZ%2BaxsPhpdZDyRRFhG0sPiOE6ldKBg2lRg4xF1YCDIIIKN7DGgD3gH%2BBXwejKZfPrs2tPs%2FvPN2bKuYR1nd7xLKBSSJeqoXKnERjPwNWAG%2BLn2rZuM%2B4Tpml6vaWlp4eLcxVusZq5lCgVgOVKJjRqdX86ffL4D5wIoZACnTpw4wRMdT96i%2FImOJxERAs4uVyqxUacF%2FPdiCj%2BjdRBRGFtwXVdG0sPSdbhTmkYbpH98p2RmM2JZlig1vl0GWo4NQ%2Fn%2Bs5pKRXfwjweaxy7TND3HcRZbfC6X8xVPVQlGy7WxVWlO5XRXFXm6EZmrQuSXYyPE3SiVoEhE6Wyr0u2rumO6zv%2B21AFdQAswC1wCMuUCXCmyWQus103Qg8qlDO0lxwOb%2Fl4FiK3AB3VS%2FuKKLtK%2FgbeAnwG%2FvUODuRw%2FFrR0H1UC75fwu8oJ%2FhFsW5VIG%2FBUgEIN6Y65O4AHu4Ap0zQ9y7LEcZyb9lRBUHQcRyzL8unZVBW5bFWAvAp%2BhDQ2g4F47dUYtlU6obXA54DnVdFLekjUGGifh4AFy7LEdV3xj3X9I66m0QZpGm2QrsOd0j%2B%2BU0bSw5KZzYjrun6HWlAd961i4FfCj0aN1Usau%2Bc1lmuXPFwvAEumUut7tQQvAb%2FXb%2FT0bCAej9cODg7yt%2Bm%2F8q2%2F7OUHZ76PnZ1k2p0mJzlykmPancbOTnL0whHs7CQfb%2B5mx2d3sH79%2BtCRI0c6FeaOr9ICrIQfLvA%2B8BGNXxi4R6HrisJVUWrxAVW2oMFf0Aczim8o3kV6enowDIPjF9%2Fk%2BMU3S3rrjzMMg56eHr%2BxP7qKFbASfojG6kpeDGs1tiW53RxwWT%2Bin5q8w4xpQK5evQpAR30H7ZH2khNvj7TTUd8BgD4rqmu1ZKX8qNeY%2BfHz4zlXDgT5E8tpCTUq7XSBC4Euv8227TV9fX1E73%2BYtvo27BmbS9cvFVTY3bSRFza9yOcf6Gfmygy7d%2B%2Fm%2FPnzF4DvrsBLhnJlJfwIKXxv1PheAE4qK6p4H9AGbNKTuhngBPBPXYRe4IemaT5kWZbR19fHNbmGnZ1k4r3U4glDR30Hm5qjbGjsImJEOHbsGHv27JFz5869o0eFq01Jq%2BmHAXwI6FFKagMTgHM7GzFDS%2BoeLSMv7zjzC9x4Y7gxFovVDAwMEI1GaWlpWSzRVCrFwYMH%2FXfxZ4AfAa8B%2F7lDaGg1%2FQgp43lfK0yqtRMuJa3ceKe5DfgYsCYAZ2ngD8CfAkzqTpW7xY%2F%2FSznyX%2FVeUb2kVmX4AAAAAElFTkSuQmCC">ERROR</object></object></object></div><div id="eyes-b"></div><div id="eyes-c"></div></div> <!-- that's a PNG with 8bit alpha containing two eyes -->
   <div class="nose"><div><div></div></div></div>
   <div class="empty"><div></div></div>

   <div class="smile"><div><div><span><em><strong></strong></em></span></div></div></div>
   <div class="chin"><div>&nbsp;</div></div>
   <div class="parser-container"><div class="parser"><!-- ->ERROR<!- --></div></div> <!-- two dashes is what delimits a comment, so the text "->ERROR<!-" earlier on this line is actually part of a comment -->
   <ul>
    <li class="first-part"></li>
    <li class="second-part"></li>
    <li class="third-part"></li>
    <li class="fourth-part"></li>

   </ul>
   <div class="image-height-test"><table><tr><td><img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAIAAAFSDNYfAAAAaklEQVR42u3XQQrAIAwAQeP%2F%2F6wf8CJBJTK9lnQ7FpHGaOurt1I34nfH9pMMZAZ8BwMGEvvh%2BBsJCAgICLwIOA8EBAQEBAQEBAQEBK79H5RfIQAAAAAAAAAAAAAAAAAAAAAAAAAAAID%2FABMSqAfj%2FsLmvAAAAABJRU5ErkJggg%3D%3D" alt=""></td></tr></table></div>
  </div>
 </body>
</html>